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2 5 sandy or earthy matter mixed W113i: a variable ati e 0 ilr am UNITEDSTATES PATENT OFFICE.

\VINIFRED M. ROBINSON, OF SHUBENACADIE, CANADA, ASSIGNOR OF ONE- IIALFTO SAMUEL M. BROOKFIELD, OF HALIFAX, CANADA.

CONCRETE.

SPECIFICATION forming part of Letters Patent No. 617,427, dated January10, 1899.

Application filed July 26, 1898. Serial No. 686,973. (No specimens.)

or like material, and iron, whicmgaciion of a salt solution is massedand hardened by the production of ferric h 'drate.

The object of my lnven iion 1s to solidify the oxidized mass to producea concrete of greater strength, hardness, and durability than theconcrete specified.

My invention consists in the addition thereto of flour of sulfur andwetting the dry mixture WI a sa ura e solution of silicate of soda.

A concrete now in use and of which my invention is an improvement iscomposed of a mixture of small broken stone or ravel and propor 1011 o11011 in a low state of oxidation or metallic iron comminuted crushedhemt r owdei'ed or sulfate of iron mixed l Wh en placed 1n positionwetted with riiie or other like saturated alkaline solution 0 e ectmassing and hardening. I have found that this concrete while excellentunder certain conditions is improved for roadwork by the addition offlour of sulfur to the dry mixture and aftermosition as the top coating.of a roadway wetting it with a saturated solution of silicate of sodaand then with the brine or alkaline solution, the effect being men thesetting of the concrete and make the unity of the component parts morebinding and producing a very hard surface. The proportion of flour ofsulfur varies from one to two per cent., an e union is formed of theiron and sulfur and other materials, which is greatly facilitated bysaturation with the soda solution. A mass is thereby formed free rom anyenc ency to crumble either by action of frost, excessive moisture ordryness, or from other natural causes.

In using the concrete for making a Walk or roadway the bed is laid withcoarse stones evened up with broken stone. The dry materials, consistingof small stone ofgravel', earthy matter, and iron mixed with flour ofsulfur, is then sifted or spread over the bed and pounded to fill theinterstices to make a smooth surface. The surface is then wetted orsaturated with the solutionof silicate of soda and afterward wit'lifliesalt'soliition.

I claim as my invention A concrete composed of small stones or gravel,sand or earthy material, iron oxidated or comminuted and flour ofsulfur, mixed dry, and hardened by wetting with saturated solutions ofsilicate of soda and salt, substantially as set forth.

\VINIFRED M. ROBINSON.

Witnesses:

ANDREW J. LITCHFIELD, HORACE '1. FOGG.

Hi I a H a 8,1861, Pavlngfioncrete.

